In 2003 former U.S. Deputy Assistant Secretary of State Jonathan Winer told Congress:

Elements of the Brotherhood reached Saudi Arabia and the other Gulf states following the Egyptian disaspora. Egyptian Salawfi Muslims involved in the Brotherhood came into closer contact with Saudi Wahabism, and the Brotherhood began to access to Saudi and other Gulf state funds through the zakat process. As a result, Islamic militants had access to revenue streams with no controls…

Ever since the rise of Nasser inspired Arab nationalism and his left wing leaning following nationalization of Suez Canal, the pro-West Saudi Kingdom with a view to keep their regime intact closely watched the anti-Nasser activities of the MB and therefore courted them seriously. Accordingly, the Saudi King with an objective to counter Nasserism funded the MB members for establishing their faculty in the Islamic University of Medina and also allowed them to propagate in various public forum that communism and socialism were totally antithetical to Islam. Since then the MB maintained very good relation with royal family and became its ideological protectorate. Saudi Monarchy’s financial and ideological support to MB worked as catalyst in making the organisation very popular among the Muslim youths and students all over the Muslim world.

And lastly, Alyssa Lappen has called the Muslim Brotherhood, “the best funded Islamist organization.” Considering the money geyser of zakat from Saudi Arabia, that’s no surprise.